U.S. patent application number 11/865939 was filed with the patent office on 2008-06-05 for touch panel.
This patent application is currently assigned to SMK CORPORATION. Invention is credited to Takehiro Egami, Naomi Nakayama.
Application Number | 20080131624 11/865939 |
Document ID | / |
Family ID | 39145437 |
Filed Date | 2008-06-05 |
United States Patent
Application |
20080131624 |
Kind Code |
A1 |
Egami; Takehiro ; et
al. |
June 5, 2008 |
TOUCH PANEL
Abstract
A touch panel for use in an ultra-high resolution display
includes a transparent film substrate having one surface made of
PET or the like and a transparent electrode film made of ITO film
or the like that is formed on the transparent film substrate. A
surface of the film substrate opposite the surface on which the
transparent electrode is formed has a coating layer including a
filler. The filler has an average particle size of 0.1 .mu.m to
0.01 .mu.m, and the coating layer is formed to have a surface
having arithmetic particle roughness (Ra) of 0.1 .mu.m to 0.01
.mu.m, whereby the Ra of the surface of the coating layer is formed
to 1/2000.sup.th to 1/4000.sup.th of the pixel pitch of a display
to which the touch panel is attached.
Inventors: |
Egami; Takehiro;
(Toyama-shi, JP) ; Nakayama; Naomi; (Toyama-shi,
JP) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
SMK CORPORATION
Tokyo
JP
|
Family ID: |
39145437 |
Appl. No.: |
11/865939 |
Filed: |
October 2, 2007 |
Current U.S.
Class: |
428/1.1 |
Current CPC
Class: |
G06F 3/045 20130101;
C09K 2323/00 20200801; Y10T 428/10 20150115 |
Class at
Publication: |
428/1.1 |
International
Class: |
C09K 19/00 20060101
C09K019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2006 |
JP |
JP 2006-328419 |
Claims
1. A touch panel comprising: a transparent film substrate and a
transparent electrode film formed on one surface thereof; wherein
an arithmetic particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m is
formed on a surface of the film substrate opposite to another
surface on which the transparent electrode is formed, and the
arithmetic particle roughness (Ra) is formed to 1/2000.sup.th to
1/4000.sup.th of the pixel pitch of a display to be attached to the
touch panel.
2. A touch panel comprising: a transparent film substrate; a
transparent electrode film formed on one surface of the transparent
film substrate; a coating layer provided on another surface of the
transparent film substrate, and a filler of fine particles
distributed and aligned substantially uniformly in a layer within
resin in the coating layer; wherein the filler has an average
particle size of 0.1 .mu.m to 0.01 .mu.m, a surface of the coating
layer is formed to exhibit an arithmetic particle roughness (Ra) of
0.1 .mu.m to 0.01 .mu.m, and the Ra is formed to 1/2000.sup.th to
1/4000.sup.th of the pixel pitch of the display to be attached to
the touch panel.
3. A touch panel comprising: a transparent film substrate and a
transparent electrode film formed on one surface of the transparent
film substrate; wherein a mold formed to have an arithmetic
particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m is pressed
against the other surface of the film substrate on the side
opposite that on which the transparent electrode is formed, thereby
forming the other surface of the film substrate such the it
exhibits arithmetic particle roughness (Ra) of 0.1 .mu.m to 0.01
.mu.m, the Ra being selected to be 1/2000.sup.th to 1/4000.sup.th
of the pixel pitch of a display to be attached to the touch
panel.
4. A touch panel film according to claim 1 wherein an anchor layer
is disposed between one surface of the film substrate and the
transparent electrode, and a filler of fine particles is
distributed and aligned substantially uniformly in a layer within
resin in the anchor layer; the filler having an average particle
size of 0.1 .mu.m to 0.01 .mu.m, thereby forming an arithmetic
particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m on a surface of
the anchor layer, the Ra being formed between 1/2000.sup.th to
1/4000.sup.th of the pixel pitch of the display to be attached to
the touch panel.
5. A method for forming a touch panel, comprising the steps of:
forming a transparent electrode film on a transparent film
substrate; and forming a surface of the transparent film substrate
opposite to another surface on which the transparent electrode is
formed, wherein the formed surface has an arithmetic particle
roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m, and wherein the Ra is
selected to be between 1/2000.sup.th to 1/4000.sup.th of the pixel
pitch of a display to be attached to the touch panel.
6. A method for forming a touch panel, comprising the steps of:
forming a transparent electrode film formed on one surface of a
transparent film substrate; forming a coating layer provided on
another surface of the transparent film substrate, and a filler of
fine particles distributed and aligned substantially uniformly in a
layer within resin in the coating layer; wherein the filler has an
average particle size of 0.1 .mu.m to 0.01 .mu.m, a surface of the
coating layer is formed to exhibit an arithmetic particle roughness
(Ra) of 0.1 .mu.m to 0.01 .mu.m, and the Ra is formed to
1/2000.sup.th to 1/4000.sup.th of the pixel pitch of the display to
be attached to the touch panel.
7. A method for forming a touch panel, comprising the steps of:
forming a transparent electrode film formed on one surface of a
transparent film substrate; forming a mold having an arithmetic
particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m; pressing the
mold against the other surface of the film substrate on the side
opposite that on which the transparent electrode is formed, thereby
forming the other surface of the film substrate such the it an Ra
of 0.1 .mu.m to 0.01 .mu.m, the Ra being selected to be
1/2000.sup.th to 1/4000.sup.th of the pixel pitch of a display to
be attached to the touch panel
8. A touch panel film according to claim 2 wherein an anchor layer
is disposed between one surface of the film substrate and the
transparent electrode, and a filler of fine particles is
distributed and aligned substantially uniformly in a layer within
resin in the anchor layer; the filler having an average particle
size of 0.1 .mu.m to 0.01 .mu.m, thereby forming an arithmetic
particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m on a surface of
the anchor layer, the Ra being formed between 1/2000.sup.th to
1/4000.sup.th of the pixel pitch of the display to be attached to
the touch panel.
9. A touch panel film according to claim 3 wherein an anchor layer
is disposed between one surface of the film substrate and the
transparent electrode, and a filler of fine particles is
distributed and aligned substantially uniformly in a layer within
resin in the anchor layer; the filler having an average particle
size of 0.1 .mu.m to 0.01 .mu.m, thereby forming an arithmetic
particle roughness (Ra) of 0.1 .mu.m to 0.01 .mu.m on a surface of
the anchor layer, the Ra being formed between 1/2000.sup.th to
1/4000.sup.th of the pixel pitch of the display to be attached to
the touch panel.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S.C.
.sctn.119 to Japanese Patent Application No. 2006-328419, filed
Dec. 5, 2006, and which is hereby incorporated herein by reference
in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a touch panel used as an
input device and provided on the surface of displays and the like
of various electronic devices.
BACKGROUND OF THE INVENTION
[0003] In recent years, there has been widespread application of
electronic devices equipped with touch panels in the display
screens thereof. However, extraneous light and reflections cause
glare on the surface of these touch panels and affect the
visibility of the display. To avoid this, the touch panel film may
undergo surface processing known as antiglare processing, whereby
the surface of the touch panel is made coarser to scatter light. A
method for making the film surface coarser is to coat the film
surface with a UV curing resin in which fine particles, known as
filler, are dispersed, and then to cure the resin to form a
roughness of several microns.
[0004] As described for example in Japanese Unexamined Patent
Application Publication No. 2004-351744, which is which is
incorporated herein by reference in its entirety, a touch panel 2
using this type of touch panel film 1 is configured as shown in
FIG. 4. The touch panel 2 is equipped with a touch panel substrate
4, which is a transparent insulative substrate, provided on the
front surface of an electronic device liquid crystal display 3. A
transparent electrode 7b of ITO (indium-tin oxide) film or the like
is provided in a predetermined pattern on the surface of the touch
panel substrate 4. Then the touch panel film 1 is attached so as to
cover the touch panel substrate 4.
[0005] The touch panel film 1 is formed from a film substrate 5 of
PET (polyethylene terephthalate) or the like, and on the surface
facing the rear surface of the touch panel substrate 4, a
transparent electrode 7a of ITO film or the like is provided via an
anchor layer 6 at a predetermined spacing of gap g with the
transparent electrode 7b of the touch panel substrate 4. Moreover,
on the front surface of the film substrate 5 of the touch panel
film 1, a filler 8 having a particle size of approximately several
microns is affixed with a UV curing resin 9.
[0006] However, with the higher resolution of liquid crystal
displays in recent years, although the above-described type of
antiglare processing with particles of several microns in size is
able to suppress reflections and other glare, because light rays
from the liquid crystal material have a fine pitch, the filler and
roughness thereof cause the light from the liquid crystal to
reflect diffusely, creating glare and causing color separation in
the liquid crystal pixels, thereby noticeably degrading the
visibility of the display.
[0007] Thus, Japanese Publication No. 2004-3517441 discloses a
touch panel to which antiglare processing is carried out using a
filler of fine particles having an average primary particle size of
100 nm or less, forming a ten-point average roughness Rz of at
least 100 nm but less than 500 nm.
[0008] The prior art disclosed in the Japanese Publication No.
2004-3517441 corresponds to a liquid crystal display having a high
resolution known as eXtended Graphics Array (XGA) resolution and a
pixel pitch of approximately 123 dpi, but does not provide
sufficient effect in suppressing glare and the like for the higher
resolution liquid crystal displays of today such as Wide XGA (WXGA)
and Super XGA (SXGA) displays having pixel pitches of approximately
0.2/mm.
SUMMARY OF THE INVENTION
[0009] The present invention was devised in consideration of the
above-described prior art, and it is an object of the present
invention to provide a touch panel having a simple configuration
wherein no degradation of visibility occurs even when used in a
high resolution display.
[0010] The present invention is directed to a touch panel
comprising a transparent film substrate of PET or the like, and a
transparent electrode film of ITO film or the like formed on one
surface thereof; wherein an arithmetic particle roughness Ra of 0.1
.mu.m to 0.01 .mu.m is formed on the film substrate surface
opposite that on which the transparent electrode is formed, and the
Ra is formed to be between 1/2000.sup.th to 1/4000.sup.th of the
pixel pitch of the display to be attached.
[0011] Moreover, the touch panel further comprises a coating layer
provided on another surface of the film substrate, and a filler of
fine particles distributed and aligned nearly uniformly in a layer
within resin in the coating layer; wherein the filler has an
average particle size of 0.1 .mu.m to 0.01 .mu.m. The coating layer
is formed to have an Ra of 0.1 .mu.m to 0.01 .mu.m, of
1/2000.sup.th to 1/4000.sup.th of the pixel pitch of the display to
be attached.
[0012] The touch panel according to the present invention may be
produced using a mold formed to have an Ra of 0.1 .mu.m to 0.01
.mu.m that is pressed against the other surface of the film
substrate on the side opposite that on which the transparent
electrode is formed, thereby forming an Ra of 0.1 .mu.m to 0.01
.mu.m on the other surface of the film substrate and forming an Ra
of 1/2000.sup.th to 1/4000.sup.th of the pixel pitch of the display
to be attached.
[0013] Additionally, an anchor layer may be disposed between one
surface of the film substrate and the transparent electrode. A
filler of fine particles is distributed and aligned nearly
uniformly in a layer within resin in the anchor layer; the filler
having an average particle size of 0.1 .mu.m to 0.01 .mu.m, thereby
forming an Ra of 0.1 .mu.m to 0.01 .mu.m on the anchor layer, and
forming an Ra of 1/2000.sup.th to 1/4000.sup.th of the pixel pitch
of the display to be attached.
[0014] The present invention is capable of providing an inexpensive
touch panel having good visibility, without any reflection from
extraneous light, and without occurrence of display glare and color
separation, even when used in a high resolution display.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention will become more readily apparent from the
Detailed Description of the Invention, which proceeds with
reference to the drawings, in which:
[0016] FIG. 1 is a schematic cross section drawing of a touch panel
consistent with the principles of the present invention.
[0017] FIG. 2 is a schematic cross section drawing of another touch
panel consistent with the principles of the present invention.
[0018] FIG. 3 is a schematic cross section drawing of yet another
touch panel consistent with the principles of the present
invention.
[0019] FIG. 4 is a schematic cross section drawing of a typical
conventional touch panel.
[0020] In the figures, elements that are repeatedly illustrated are
consistently identified by a single reference numeral.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The following table provides a key to the reference numerals
and elements depicted in the drawings:
TABLE-US-00001 10 Touch panel 12 Film substrate 14 Touch panel film
16 Anchor layer 18a Transparent electrode film 18b Transparent
electrode film 20 Touch panel substrate 22 Housing part 24 Display
26 Coating layer
[0022] Embodiments of the present invention are described below
with reference to the drawings. FIG. 1 shows a first embodiment of
the present invention wherein a touch panel 10 is provided with a
touch panel film 14 comprising a film substrate 12 made of PET or
the like and having a thickness of approximately 180 to 200 .mu.m,
for example. A transparent electrode 18a made of ITO film or the
like is formed in a predetermined pattern on the rear surface of
the touch panel film 14 with an anchor layer 16 disposed
therebetween. The touch panel film 14 is affixed to the film
substrate 12, which faces a touch panel substrate 20 on which a
transparent electrode 18a and an opposing transparent electrode 18b
are formed with a small gap therebetween. Then, the touch panel
substrate 20 is affixed to the display surface of a liquid crystal
or other display 22 formed from glass or transparent resin.
[0023] The film substrate 12 of the touch panel film 14 may be
formed, for example, of polyethylene terephthalate (PET), or a
transparent polymer such as a polyester polymer, a polycarbonate
polymer, diacetyl cellulose, an acrylic polymer and so on.
Moreover, a styrene polymer such as polystyrene, polyethylene, an
olefin polymer such as polypropylene, a polyvinyl chloride polymer,
or an amid polymer typified by nylon or aromatic polyimide and the
like having excellent transparency may also be used. Additionally,
an imide polymer, a sulfone polymer, a vinyl alcohol polymer, a
vinylidene chloride polymer, an arylate polymer, and the like
having excellent appropriate transparency may be used according to
the application.
[0024] The transparent electrode 18 is formed by vacuum-based thin
film formation technology such as sputtering, and the anchor layer
16 is coated with a material and formation method similar to that
of a curing resin 25 of a coating layer 24, as further described
herein below.
[0025] On the rear surface of the film substrate 12 of the touch
panel film 14 is formed a coating layer 24, and in the coating
layer 24 is dispersed a filler 26 of particles that are distributed
and aligned substantially uniformly in a layer within the curing
resin 25. The filler 26 has an average particle size of 0.1 .mu.m
to 0.01 .mu.m, and the arithmetic particle roughness Ra of the
coating layer is 0.1 .mu.m to 0.01 .mu.m. Additionally, the Ra of
the coating layer 24 is 1/2000.sup.th to 1/4000.sup.th of the pixel
pitch of the display 22 to which the touch panel is attached.
[0026] As examples of the curing resin 25 of the coating layer 24,
a UV curing resin is preferable, and monofunctional acrylate or
multifunctional acrylate is used.
[0027] For the filler 26 in the curing resin 25 of the coating
layer 24, a substance comprising a metallic oxide or a metallic
fluoride such as Al.sub.2O.sub.3, Bi.sub.2O.sub.3, CeO.sub.2,
In.sub.2O.sub.3, In.sub.2O.sub.3.SnO.sub.2, MgF.sub.2,
Sb.sub.2O.sub.5, Sb.sub.2O.sub.5.SnO.sub.2, SiO.sub.2, SnO.sub.2,
TiO.sub.2, Y.sub.2O.sub.3, ZnO, or ZrO.sub.2 may be used. Moreover,
two or more substances comprising a metallic oxide or a metallic
fluoride may be combined to produce the filler 26.
[0028] The coating layer 24 may be formed using, for example, a
roll coater, doctor knife, bar coater, gravure roll coater, curtain
coater, spin coater or the like. Conventional spray or dipping
methods or the like may also be used.
[0029] Antiglare processing is performed on the touch panel 10 of
this embodiment to form a roughness finer than the corresponding
pixel pitch of the display 22, so that even when using an
ultra-high resolution display 22 having a pixel pitch of 0.2 mm or
smaller, glare from extraneous light and reflections is suppressed,
display glare and color separation do not occur, and the visibility
is good.
[0030] Next, a second embodiment of the touch panel of the present
invention is explained with reference to FIG. 2. Configurations
that are the same as in the above-described first embodiment are
assigned the same reference numerals, and their descriptions are
omitted herein.
[0031] A touch panel 30 is provided with a touch panel film 34
comprising a film substrate 32 made of PET or the like, and having
a thickness of approximately 180 to 200 .mu.m, for example. An
anchor layer 36 is provided on the touch panel substrate side
surface of the film substrate 32, and a transparent electrode 38a
is formed in a predetermined pattern on the front surface of the
anchor layer 36. A filler 37 of particles are distributed and
aligned substantially uniformly in a layer of curing resin 39 of
the anchor layer 36. The filler has an average particle size of 0.1
.mu.m to 0.01 .mu.m, and an Ra of the anchor layer 36 is 0.1 .mu.m
to 0.01 .mu.m. Additionally, the Ra of the anchor layer 36 is
1/2000.sup.th to 1/4000.sup.th of the pixel pitch of the display to
which the touch panel is attached. The curing resin 39 of the
anchor layer 36 may comprise the same material as the curing resin
25 of the coating layer 24.
[0032] A third embodiment of the touch panel of the present
invention is explained with reference to FIG. 3. Configurations
that are the same as in the above-described embodiments are
assigned the same reference numerals, and their descriptions are
omitted herein. A touch panel 40 is provided with a touch panel
film 44 comprising a film substrate 42 made of PET or the like, and
having a thickness of approximately 180 to 200 .mu.m, for example.
A surface having an Ra of 0.1 .mu.m to 0.01 .mu.m is formed on a
side of the touch panel film 44 opposite that on which a
transparent electrode 38a similar to that of the above-described
second embodiment is formed. The surface of the touch panel film 44
is formed by heating and then pressing thereto a mold 43 of metal
or the like having a surface on which is formed a pattern having an
Ra of 0.1 .mu.m to 0.01 .mu.m. The surface of the mold 43 may be
treated, for example, with a TEFLON treatment or other mold release
process.
[0033] Similar to the second embodiment, an anchor layer 36 is also
provided on the surface of the film substrate 42 on the touch panel
side, and a transparent electrode 38a is formed in a predetermined
pattern on the surface of the anchor layer 36. A filler 37, similar
to that described above, of particles that are distributed and
aligned substantially uniformly in a layer is provided within the
curing resin 39 of the anchor layer 36, and the Ra of the anchor
layer 36 is 0.1 .mu.m to 0.01 .mu.m. The arithmetic particle
roughnesses (Ra's) on the front and rear surfaces of the touch
panel film 44 are 1/2000.sup.th to 1/4000.sup.th of the pixel pitch
of the display to which the touch panel is] attached.
[0034] The touch panel of the present invention is not limited to
the above-described embodiments, and a number of methods for
forming surface roughness may be selected as appropriate. In
addition to the above-described use of a filler or of mold
transfer, etching, sandblasting, embossing, and the like may also
be used to process the layer surfaces to achieve the desired Ra's.
Moreover, the surface coarseness of the anchor layer can be set
appropriately according to the pixel pitch of the display being
used. In addition to ITO films, indium-zinc oxide (IZO) or other
transparent electrode material may be used for the transparent
electrode film. The thickness and qualities of the film substrate
and other materials may also be set appropriately
* * * * *